Telephone system.



H. J. HERINK.

TELEPHONE SYSTEM.

APPLICATION FILED FEB.8, new.

1,269, 1 8 1 Patented June 11. 1918.

5 SHEETS-SHEET l- H. J. HERINK.

TELEPHONE SYSTEM.

APPLICATION FILED FEB. 8. l9l6.

1 ,269, 1 8 1 Patented June 11, 1918.

5 SHEETS-SHEET 2- H. J. HERINK.

. TELEPHONE SYSTEM.

APPLICATION FILED FEB. 8. 19m.

5 SHEETS-SHEET 3.

H. J. HERINK.

TELEPHONE SYSTEM.

APPLICATION FILED FEB. 8.1916.

1,'269,-1 81 Patented June 11, 1918.

5 SHEETS-SHEET 4- l QR:

N H Hg; 782,672 67),; 0 i *5 H. l. HERINK.

TELEPHONE SYSTEM.

APPLICATION FILED FEB. 8. 1916.

- Patented June 11, 1918.

5 SHEETS-SHEET 5- y/Lu: ri e HENRYJAMES HERINK, OF LONDON, ENGTI'.

.AND, ASSIGNOR TO THE RELAY AUTOMATIC TELEPHONE CQMPANY, LIMlTiiD, OF LONDON, ENGLAN TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented June 11, 1918.

Application filed February 8,1916. Serial No. 78,977.

To all whom it may concern:

Be it known that I, HENRY JAMES HERINK, a subject of the King of Great Britain, residing at Marconi House, Strand, London, England, have invented new and useful Improvements in Telephone Systems, of which the following is a specification.

It is a well known fact in telephony that the traffic variations of small groups of lines are relatively greater than the variations of large groups. The number of junction lines and apparatus required for carrying a given traffic is therefore, to a considerable extent, dependent on the grouping of the lines and the distribution of the calls.

The chief object of this invention is to reduce the number of such connecting means and to increase their efliciency.

Generally speaking, owing to the fact just mentioned, every attempt to increase the efficiency of the connecting means envisages some method of increasing the accessibility thereof. According to the present invention, this is effected by the use of so-calledoverflow lines or links so arranged that in case the outgoing junction lines of a group are all engaged, the connection can be extended through an overflow link to another similar group of the same switching stage, in which group such link has access to the junctions outgoing therefrom. Preferably the incoming overflow links are given the same connecting facilities as other incoming lines of the group and thus have access to the overflow links outgoing from that group,

so that if all the outgoing junctions of this second group should also be engaged, the connection can be extended to a third group, and so on. Other features of the invention will be described with reference to the accompanying drawings, Figures 1, 2 and 3 of which are schematic representations of three different forms of the invention. Fig.

4 illustrates the invention as applied to a system using primary and secondary preselectors. Figs. 5 and 6 show actual circuits which are suitable for any of the arrangements described but more particularly for enter into the adjacent group in the same manner as the other incoming lines of that group, and have the same connecting facilities as those lines. Thus, in case a calling incoming line of a group should find all outgoing junctions of that group engaged, connection is established with an idle overflow link. The calling line is thereby extended to the next line group in which it immediately appears as calling, and is connected to an idle outgoing junction. Should all the junctions of this second group be engaged, the connection is extended through a second overflow link to a third group, and so on.

By this arrangement of overflow links,

every incoming linev is given access to any.

group of outgoing junctions or, in other words, the outgoing junctions are made available to all incoming lines. Consequently the number of lines required for carrying the traffic is reduced, and the traflic carrying efliciency of the line is increased.

The invention is entirely independent of the kind of apparatus used for establishing the connection, and may be used in manual systems as well as in automatic and semiautomatic systems.

In a manual system for instance, an A operatormay be provided with one or more links leading to another A operator, so that in case all junctions belonging to one operators position should be engaged, or if all B operators accessible from one operators position should be busy, a calling line can be plugged on to another A position where the connection can be efl'ected.

rise

. s 111 L 15;. la

Well as the links incoming to that group may 7 he multipleol over coll-finders associates with the outgoing junction lines, and Withthe outgoing links the arrangement for selecting and starting an idle cell-finder being ch that no link is taken into use until outgoing junctions of the group engegecl. 'lhe number of outgoing junctions and the number of links of each group we of course, immeterisl the invention: and; may be any number consistent with the tmllic requirements For instance, there may be only one outgoing junction 2') ollottetl to each group of incoming lines a as shown in Fig 2, the cinching outgoing lines being links so seal in the menner tlescribeo; y re lucing he member of junctions in dually ellottecl to com scoop of incomlines and ot the s is time increasing illlil'lbei oi licks the totel number of out- J L lotions i'equirecl s reducech Whereas total number of smut elation oetweei'l the u iiictions and the number o'l' links, 1

economical to hiiicel point or: vie theref e ent on the tiellic COHQlLLiODS of tl v OI. the port of the ei'chzmge to which to be opp 1- l each P011 to difll oh case M oggctl as soon as xie outgoing lines oocessiblc to it are all calling sot-- scrlber is then mitonmticelly connected with litilt over which he con' have eccess to an idle outgoing line.

his; 8 illustrates soothes form of the invention according to which the links can be better utilized by arranging them in common to two or loose groups of incoming lines Each group of outgoing junctions is then preferably adopted to ca-try only about the normal OUiZWFl-Nl ttoii'ic of the associated groups of incoming; lines While the links common for iosteince to two groups of lncoo'iing lines are suilicieot to carry the peak loads of both associated groups As the peak loads of the two groups may dill-er in time anal only rarely occur at the some time it is obvious that this arrangement allows areeluction of the total number of links.

In the draw 5113; the links common to two group-s shown to hove access to two 'joceht gtoups of outgoi junctions as Well .7 1 a a c to the appertaining h s,bot1.t cvid of;

1 Q cup have sc- 5; oi" outgoing lines, in preferably method s eec es.

links may be otherwise clistributeil without tlepotting flow. the invention 'lhus e group of links may have access to one or moi-e groups of junctions but not to other. links t shows the invention as epplieol to the preselecting; stages in systems in Wl'iich the connection with s trunk leading to the first (l t stage is established in 21 known manner over primz-uy eml socoi'iclei'y pseselectoi'sc The s vitches may be of any kind, but the scheme shown is petticulerly designed for relay switches of the cellfintler type:

1,000 subscrihers lines may be divided into 20 gioups G of 50 lines, anal his hove scce s to ill trunk lines N over intermediate junctions lil' The trunks are arranged in. three grooves C (3 and C of l? trunks each. lilech group of subscribers lines has access to six. junctions M and t to links P L primary coll-finder is associated With each such junction ohtl linlo and the subscribers lines of coco gioup are multiplied over the s ppet mining csllfinclei's v The links outgoing from one roup are moltioled over the pri moi c ll-lllXlQiS ol the sections and oil the links of the edjoccnt group that the si ches sssocizitecl with the trunks N in such o manner that the various functions ewtiloble to each group of subscribers" lines have ecc different groups C in lObiti'iOl'i. 1i ssocieteo ltl'l each group of tanks N are four link." each connected W. ,h. seconth or coll-fin iGF' otloip the collll junction The links of one groupare ii'iultipletl o? ,2 the csll finclers of the adjacent group of trunks and overflow links es shown in. the drawing The operation of the switches will now be clcscribmhwith reference to F 5 eml 6,

in which L. is a subscribers line, M on inteo mediate juwtioh N o, trunk line leading to the digit siege Cl e. primary cellfinclei' and Cl secondary cell lindeifi.

Each cullhmlerconsists of 10 groups switching relays Gtllt and 5 unit relays UR, the gcoup i'elsys being soap-tool to connect s gerticuloi group of 5 subscribers lines L or intenoecliste junctions M respectively to at corresponding member of connecting lines CL and the unit Foley s being arranged to connect the junction M or trunk N" with which the celbfimler is associstecl to one of soitl lines CL,

By lifting the receiver, the calling subscribe closes o line circuit 1. through his line Foley LR, which operates eml causes the energization of relay SR over circuit SR connects all group switching; relays G'Slt with the marking; WllGS MW thereby 'clos ing s circuit through the operating minds The juhctions ate mum; Jiecl ove: secondary coll-fiodotl to operette exactly as ers oi the trunks to find s calling lay in question.

ing of the group relay GSR corresponding to the 5-group to which the calling subscriber belongs. The relay GSR in question operates and cuts itself in a locking circuit 4 containing a locking winding of said relay and break contacts of other group relays located between the battery and the group re- This arrangement of the locking circuits of the group relays evidently prevents more than one group relay being energized at the same time if two or more calls originating in different 5-groups should occur simultaneously. The locking circuit at first also includes a relay LSR connected in parallel to a resistance R, whereby the third wires CI of the connecting links CLI are connected to the corresponding unit relays UR. A circuit 5 is therefore closed through the cut-off relay COR of the calling subscriber, third wire CI and an operating winding of the unit relay corresponding to the calling subscriber. Said unit relay energizes and locks itself over a circuit 6 containing a relay TDR which cuts off relay LSR.

As seen from the drawing, the locking circuits of relays UR are arranged in a manner similar to those of relays GSR, so that only one of the unit relays can be kept energized if two or more calls occur simultaneously in the same 5-group. Consequently, double connections are effectively prevented.

The connection is now extended to the intermediate junction M. In the mean time a secondary call-finder has been operated by the closure of circuit 7 including a relay SR or the secondary call-finder similar to SE. The secondary call-finder operates in the same manner as the primary callfinder and connects the junction M in question to the appertaining trunk N.

Upon the completion of the connection with the trunk, a third wire circuit 8 is closed extending over the whole connection and including a relay TSR, which switches the starting circuit 2 on to the next idle primary call-finder. At the same time the circuit of SR is opened and the locking circuits of the switching relays GSR and UR are branched to earth through a relay RCR and a contact 9 of relay TSR, whereby said relays are maintained energized and cut into dependence of the calling subscriber for the purpose of release of the call-finder. By the closure of the third wire circuit also the cut-off relay COR of the calling subscriber is energized, whereby the line relay LR is cut off and the short circuit of the meter SM is opened to allow the meter to be operated in the ordinary way by increase of current in the third wire.

The subscribers line circuit is now closed through an impulse relay IR which operates receiver, IR and GR deinergize, the latter opening the third wire circuit at contact 10 and the locking circuits of the switching relays of the secondary call-finder at contact 12, whereby the call-finders are released and restored to normal condition, the primary call-finder being released through the deenergization of relay TSR.

As will be seen from the above description the invention is principally independ ent of the construction of the switches, only the means for distributing the calls are such that the overflow switches are not taken into use until all outgoing junctions or trunks of the group in question are engaged. Practically, of course, it is desirable for the switches to be of a quick-acting type, as the connection between the subscribers line and an idle trunk must be completed in the short interval between the lifting of the receiver and the actuating of the dial.

Having regard to this fact the expediency of relay switches is obvious, as such switches operate almost instantaneously, but mechanical switches may also be used with advantage.

What I claim is 1. In a telephone system, the combination of a plurality of groups of incoming lines, a plurality of groups of outgoing lines, each incoming group having access to an outgoing group particularly associated with it, links adapted to connect the incoming lines of one group to the outgoing lines of another group and call-finder switches associated with the outgoing lines and each having access to the corresponding group of incoming lines and to a link associated with another group of incoming lines.

2. In a telephone system, the combination of a plurality of groups of incoming lines, a plurality of groups of outgoing lines, each incoming group having access to an outgoing group particularly associated with it,

links adapted to connect the incoming lines of one group to the outgoing lines of another group, call-finder switches associated with the links and having access to the incoming lines of the appertaining group as well as to the overflow links of an adjacent group, and call-finder switches associated with the outgoing lines and each having access to the corresponding group of incoming lines and to a link associated with another group of incoming lines.

3. In a telephone system, the combination 7 et a pltumlity eff ceiling tinese common line and e switch comprising a set of retsys end adapted to connect a ceiling line t0 the cemrnon line, the number of (selling lines being greater than the number e'f relays seed the circuit of said relays being; eontrei led in such s manner when e plurality the relays is energized ene piety can be maintainedenergized,

4-, 1:11 a telephene system the eombinetion of a plurality of setting lines a common line end switch comprising twe sets of relays end a simgte rehy adapted to extend a set at Wires common to one set 0f relays to the other set, the number of calling lines being greater than the number of relays and the circuit 0ft"- the relays of the two sets being eontrelled in such a manner that when a plurality of the relays in either set is energized one only in either set can be maintained energized,

HENRY JANIES HERINK. 

